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This paper presents a new scheme of minimizing multipath noise in mobile FM receivers. A novel logic circuit is used to compare analog signals from tuners in real time and a new analog signal is assembled from the best available audio signals. Actual road tests have shown that over 95% of noise from multipath interferences are eliminated without degradation of audio bandwidth or stereo channel separation.

The Hamming distance concept is applied to modulation code to improve the error detection capability of the demodulator. It will be helpful to increase the error correction capability for the subsequent error correction.

The concept and real-time implementation of an experimental home-use digital HDTV recorder is presented. An advanced motion-compensated DCT bit-rate reduction system is used to realize high-quality images at 50 Mbit/s only, thereby enabling small recording mechanics for portable applications and featuring a new high-efficiency channel code with embedded tracking information.

This paper proposes a novel integral frequency offset (IFO) estimation method for orthogonal frequency-division multiplexing (OFDM) systems, which examines the phase changes of synchronization signals in frequency domain. It is shown that the new method provides excellent IFO estimation performance with very low computational complexit (1). Index Terms--Orthogonal frequency-division multiplexing (OFDM), frequency offset, synchronization.

This paper presents a timing recovery method for VSB receivers based on a square-law device that uses both in-phase and quadrature-phase signals. Existing timing recovery schemes use second-order statistics of the real component of the VSB signals or rely on the fourth order statistics of the VSB signal magnitude. We propose an alternative timing recovery approach for VSB signals based on a square-law device that produces a DC tone with carrier phase information and a timing tone with timing frequency information (1). Index Terms--Timing Reeovery, VSB, Timing Error Detector, Spectral Line.

We consider blind equalization and carrier recovery under high-order QAM modulation, which presents more difficult operating requirements than lower-order QAM modulation. We base our design on two stages: The first is the LTE-CMA and the second is the DFE-MMA. To attain large carrier acquisition range and fast carrier recovery we first use LTE-CMA. And after that we switch to DFE-MMA to get a better blind equalization performance to combat ISI. Simulation results demonstrate the effectiveness of the proposed scheme compared with the one-stage DFE-MMA scheme (1). Index Terms--Blind Equalization, Carrier Recovery, MMA, CMA.

A study was conducted to contribute to an understanding of how technologies may be perceived to be part of technology clusters by distinguishing between clusters in perceptions and clusters in ownership. Findings indicate that perceived clusters in consumer electronics are mostly determined by functional linkages.

Consumer electronics were a big hit of the holiday shopping season last year, and it probably won't be any different this year, with flat-panel TVs, notebook computers, and digital cameras […]

Seventy-seven percent of consumer electronics purchases were influenced by Internet research according to a joint Consumer Electronics Association and Yahoo! study. 'Understanding How Consumers Use the Internet to Research and [...]

Royal Philips Electronics, Amsterdam, the Netherlands, announced plans earlier this month to buy ADAC Laboratories, Milpitas, Calif., in a deal valued at about $426 million. The ADAC acquisition will round [...]

Multipath fading is a major obstacle to be overcome in achieving high data rates for wireless LANs. Powerful equalizers needed to combat multipath are costly in terms of processing power, training sequence overhead and training time. In time-division-duplex radio systems, precoding may be used to shift the equalization burden from the receiver to the transmitter, enabling significant reductions in complexity and transmission overhead. This article describes a stabilized precoder with switched antenna diversity which achieves simple and efficient precoding for wireless LANs.

One of the main problems in Home Networked Systems is the wide diversity of technologies, application requirements and cost allowance for devices and systems in general. This is translated to a division into different islands of technology that goes down to single manufacturer systems, thus blocking the way to the system integration as the main reason for the existence of the network. It is widely accepted that achieving the interworking is the most important aspect of a system specification. Object-oriented modelling associated with proper application management mechanisms for trading and binding provides the best approach to standardisation work on home systems interworking, We take here as an example the work toward an interoperability specification for an energy management system. The system described spans several communication media and brings together several consumer and producer entities. The system aims to provide increased comfort while either minimising the usage of resources or their cost for the same level of usage. Results from installed and running systems show the success of the approach.

In recent years, error recovery on image compression methods, especially on VQ, has been an intensive research field. This paper presents a new pixel-based image reconstruction method (PIR) for recovering the lost blocks caused by transmission errors over noisy channels. Since there are high statistical correlations between the neighboring pixels of an image, PIR reconstructs the lost pixels using codebook search according to their adjacent pixels. In addition, an accelerating technique to shorten the execution time of the reconstruction is also proposed. The experimental results have shown that our PIR algorithm can efficiently and effectively recover the lost pixels. Moreover, If the image is complex or the size of the lost block is large, PIR is superior to the previous work, SMVQ. Besides, unlike SMVQ, which is only suitable for the VQ encoding, PIR could be applied for any image compression algorithms such as JPEG, DCT and so on.

This paper describes the design of a novel synthesis filter for real-time implementation of MPEG-2 audio decoder on a single, programmable DSP chip. In the first phase of our design we propose a fast subband synthesis filter bank employing a decomposed IDCT block with reduced multiplication stages, shared by both MPEG-1 and MPEG-2 decoders. In the second phase of the design, a parameter analyzer block is adopted to take advantage of the multichannel computing structure in MPEG-2 thereby further reducing the number of MAC operations. In the final phase, we propose a low-cost decoder employing unorthodox methods of boosting performance by gracefully degrading quality of service. The overall runtime of the decoder has been reduced by 60% when compared to the modified ISO decoder employing a synthesis filter bank with fast IDCT block. Real-time performance validations have been made by re-tuning time-critical code sections for both native VLIW and DSP architectures. The final implementation successfully passes all ISO/IEC MPEG-2 audio compliance tests and achieves near-transparent audio decoding and signal reconstruction on the fly.

The authors have developed a 4.7 Gbyte Rewritable Disc System having the following features: (1) a re-writable function added to a DVD-R incremental-write system, (2) a re-writable disc being physically compatible with DVD-ROM.

This paper presents an efficient software host/co-processor architecture for the implementation of MPEG-4 Audio composition. The proposed solution is based on a specific partition between general-purpose tasks and DSP-oriented functionality, thus achieving portability, efficient partitioning of the processing resources and memory management.

We have developed techniques to read DVD-RAM discs with DVD-ROM drives. The key techniques are the reduction of feedthrough in the focusing error signal, the reduction of the push-pull signal offset, and the half tracking jump function.

Digital television is based on computationally intensive MPEG-2 audiovisual compression standard. Until recently MPEG-2 decompression required special hardware for standard TV resolution. New microprocessors with multimedia instructions enable decompression of MPEG-2 in software. In this paper we investigate software MPEG-2 decompression for HDTV. Processing requirements for HDTV are formulated. Results of experiments show that realtime software decompression of HDTV is possible on multiprocessing machines. Microprocessors operating in gigahertz range will enable software decompression of HDTV on home PC's.

This paper presents the design, implementation and test results of a complete wideband CDMA modem with a modulator and a demodulator for use in next-generation mobile stations. The modem is based on NTT DoCoMo's proposal for the next generation W-CDMA air interface. The modulator supports multicode transmission capability, which enables three dedicated physical channels to be transmitted under a single radio link identification. The receiver consists of a searcher, three fingers and combiner and each finger can demodulate three dedicated physical channels simultaneously. For coherent QPSK data demodulation, a novel phase estimation algorithm has been employed. In this algorithm, a finger selects the minimum value after comparing four phase prediction values to the previous one to compute the correct phase. It has been shown that the proposed algorithm outperforms the WMSA proposed by NTT DoCoMo. The proposed mobile station modem was implemented with FPGAs and verified by the board-level experiment. Experiments have verified that the modem fully complies with the specification and is capable of up to 384Kbps data transmission when using multicode transmission.

The increasing use of Embedded Microprocessor Core (EMC) has become a popular trend for the embedded systems. The EMC development is a complex interactive process with the algorithm, the software and the hardware. This paper presents a software/hardware co-design methodology to deal with the EMC design problems. The proposed stepwise method extracts the algorithm's features and maps them onto the EMC's architecture by performing the analysis on the system level. The optimization is taken in both software and hardware domains so that the designed EMC can be specific to the algorithm. An EMC design for the variable length coding (VLC) applications is exemplified in the paper to illustrate the design procedure. Keywords: Software/Hardware Co-design, Embedded Microprocessor Core.

An architecture which seamlessly integrates multiple audio decoders onto a single DSP is presented. A new concept in the form of an open software architecture is implemented which allows third party owned intellectual property in the form of specialized software modules to co-exist as value-added post decoder processing phases. This modular software architecture maintains flexibility and adaptability for future decoder and post processing integration. The means by which this architecture supports post processing functions across decoders is the focus of this paper.

In the convergence control system with the Lagrange interpolation of high degree, the unexpected movement problem of other sampling points in case of a change of a seed point was found. This paper proposes a new digital convergence system based on cubic spline interpolation to increase the quality of interpolation as well as to solve the problem. The system was modeled in VHDL, implemented with a chip, and applied for projection TVs.

This paper presents a generic multi-processor architecture for video processing, featuring an array of programmable application-specific coprocessors and a programmable switch-bar communication network. Key advantages of the platform are that the order of functions can be changed and that video tasks can be programmed at system and functional level using tasks of any length, by applying dynamic data-flow. This modular concept is cost-effective and suitable for a large range of applications and features in the video domain. The system can be well applied in combination with micro-controllers or media processors and it is used for implementing an experimental TV platform. Keywords--Video processing architecture, HW/SW co-design, programmable hardware, dynamic data flow, multi-window, multiprocessor, parallel processing, switch matrix, unified memory.

The MPEG-2 video specification is quite flexible. Many parameters in the standard must be interpreted correctly for a decoder to reconstruct encoded video data. It needs a well defined procedure to verify that a MPEG-2 decoder is compliant with the standard. This paper presents a design method of MPEG-2 video test bitstreams, which examines whether an MPEG decoder under test (D.U.T.) produces correct images. And the test bitstreams are designed to produce a uniform gray image if the DUT complies with the standard to facilitate detection of error. The presented test bitstream is composed of two parts: the first part generates an image by varying a test parameter and the second part is predictive coded with zero motion vector and a difference image which is the negative of the correct test pattern. It will cancel the test pattern and a uniform image will result if the decoder conforms to the standard. Also we analyze characteristics of test bitstream in public domain and present design method of test bitstreams.

In this paper, we propose a digital watermarking method for still images in the discrete cosine transform (DCT) domain. The adaptive watermark insertion method is employed to increase the invisibility of the inserted watermark in images, in which variable block-size is adopted depending on the characteristics of the region. Experimental results with several test images show that the proposed watermarking method is robust to several common image processing techniques, including joint photographic experts group (JPEG) compression, lowpass filtering, multiple watermarking, and cropping.

This paper presents the implementation of MPEG-2 Advanced Audio Coding (AAC) decoder on a fixed-point DSP. AAC is a powerful coding algorithm and offers the high-quality multi-channel surround audio. We will also discuss the implementation issue and effort in porting AA C algorithms to the DSP

Although Java has many useful programming language features for developing consumer multimedia applications, it is not widely used for multimedia application development. One of the main reasons for the lack of Java usage in consumer multimedia application development is a concern for the execution speed of Java-based applications. In this paper, we investigate the feasibility of using Java as a language for multimedia applications. As a specific multimedia application example, we have developed a Java-based MPEG-1 video decoder. We describe the design and implementation of the MPEG-1 video decoder and report our experience in optimizing the decoding performance. Based on the performance analysis results from a Java performance profiler, we have applied both general and Java-specific optimization techniques. The final implementation could decode about 28.67 frames per second on a Pentium-II 300MHz computer for a 240 x 170 MPEG-1 video bitstream, a speed-up of 2.8 times over the initial implementation. Our experience strongly suggests that the pure Java-based media processing is a feasible solution. Keywords: Java performance, MPEG-1 video decoder, performance evaluation.

This paper describes an audio system that is well-suited for use in a small confined area with many audio transmitters broadcasting different audio signals. The transmitter of the proposed system is constructed using visible light LEDs, in which current fed to the LEDs is modulated and encoded with audio information or messages. The audio system provides audio signal transmission in a free space optical link. The receiver, combined with an ear jack, is located at some distance from the transmitters. The handheld receiver is designed to demodulate the optically transmitted audio information and reproduce the messages with the ear jack. For modulating emission of LEDs, an oscillator is used to vary the frequency of on/off periods of the LEDs. The frequency of flicker is high enough to be indistinguishable by human eye and hence the LEDs appear to be constantly illuminated. Keywords: audio systems, light emitting diodes; audio broadcasting.

We have developed a highly integrated liquid-crystal-on-silicon light valve for three-panel color projector. The silicon panel was designed and fabricated by a custom 0.5[micro]m, 3-metal CMOS technology with a spatial resolution of 1024 x 768 pixels. The pixel pitch was 13.8gm and the fill factor was 91%. Six-bit digital data drivers and gamma-correction circuitry were integrated within the silicon panel for true gray scale and full color representation. The display panel was assembled with a mixed twisted nematic and birefringence liquid crystal cell for high contract ratio at CMOS compatible voltage. Contrast ratio was 100:1 at 3.5Vrms. The optical system utilized a trichroic prism assembly for both the color separation and recombination. With this trichroic prism assembly incorporating three silicon light valves, a compact and high-resolution video projector was demonstrated.

This paper studies the feasibility of various optical fiber networks for the application in the In-Flight Entertainment (IFE) system of the aircraft infrastructure. Based on ARINC Specification 628 Part 4, four different optical multiplexing schemes, that is, time-division-multiple access (TDMA), sub-carrier multiple access (SCMA), wavelength/ frequency-division multiple access (WDMA/FDMA), and code-division multiple access (CDMA), are proposed for the optical links between the cabin electronics compartment (CEC) and the area distribution box (ADB). The performance analysis has been demonstrated for each case, respectively. The results indicate the optical CDMA is not suitable for this application and the WDMA scheme can be combined with any of SCMA or TDMA scheme in such a application to enhance the system capacity. Finally, from the viewpoint of the system capacity extension and design flexibility, we show that the SCMA scheme is superior to the TDMA scheme in terms of higher cost.

Because the picture quality of watermarked motion pictures must not be degraded by the watermarking, this paper describes a new module that controls watermarking processes. The module uses a new human sight model to optimize watermark strength for each frame of a motion picture, and it prevents flickering by limiting the frame-to-frame change in watermark strength. Another advantage of this module is that it can be used in a wide range of watermarking systems. The effectiveness of the proposed module has been demonstrated in five watermarking systems.

Delivery of audio-visual objects differs from the traditional video on demand systems in the characteristics of the presentations delivered. Video on demand has mainly been about delivering MPEG-2 audio and video[1]. In the case of object based presentations such as MPEG-4 presentations, the media data and the media composition data are transmitted to a client as separate streams, typically with different QOS requirements, in the same session. Furthermore, as the number of objects in a presentation can be quite large, the overhead required to manage the session is large. Interactivity makes this problem more complex as the resources required for a session will now depend on the user behavior, especially when user interaction with objects changes the number of objects in the scene either by adding or deleting objects. In this paper, we present our recent work on delivering audio-visual services based on MPEG-4. The issues covered include object-based audio-visual (MPEG-4) servers, object scheduling, and content creation. Multimedia, MPEG-4, audio-visual services, object-based representation.

The FFT and equalizer units are core components of OFDM receivers for multicarrier reception in consumer applications. This paper presents a novel FFT architecture with adaptive scaling and a new equalizer architecture circumventing the need for explicit arithmetic division. For the example of DVB-T COFDM terrestrial digital TV reception [1], the tradeoff between complexity and performance is investigated under relevant reception conditions.

This paper focuses on the design of low cost media-on-demand servers. Limitations of single-processor architectures and their input/output subsystems are shown. An original device called autonomous media I/O module (AMIOM) is proposed. The device consists of a local CPU, a local buffer memory, and an interconnection unit that allows the communication with two subordinate buses. The objective is to migrate the stream and its control from the host and to make the I/O subsystem scalable. Features of the proposed AMIOM are presented in detail. The interconnection and operation of multiple modules are discussed. Performance of the improved design is evaluated with taking into consideration communication overheads. The effect of attaching multiple I/O devices to each of the module's subordinate buses is also analyzed. Comparison of the classical design and the improved one shows significant performance gain. Index Terms -- media-on-demand, server design, input/output subsystem.

With the advance of wireless communications technology, mobile communications has become more convenient than ever. However, because of the openness of wireless communications, how to protect the privacy between communicating parties is becoming a very important issue. In this paper, we focus on the security of the Global System for Mobile communication (GSM) networks. A secure communication architecture for the GSM network is proposed. In the proposed architecture, we use public-key cryptography for user authentication and stream cipher for message encryption and decryption. An authentication protocol and a key generation method are presented in conjunction with the proposed architecture. Cryptanalysis and operational analysis show that the authentication protocol is secure and efficient. Simulation results indicate that the key generation method can always produce key strings of evenly distributed 0's and 1's and with infinite period. Keywords: GSM Networks, Wireless Communications, Mobile Communications, Block Cipher, Stream Cipher, Authentication

This paper presents data characterizing the household AC power line in the 1-60 MHz band. Two types of measurements were performed: transmission and noise sampling. The transmission measurements were done by using the impulse channel sounding method, so both the line attenuation and the delay spread were obtained. The noise measurements include: power line background noise, appliance noise, and noise sampled over a 24 hour period. Statistical characteristics of the delay spread, frequency response and noise can be extracted from the data and used in the design of AC power line based communications systems.

In this paper, for different assembly conditions, the natural frequencies, mode shapes and amplitude fluctuation electronic speckle pattern interferometry (AF-ESPI) fringe patterns of the shadow mask were obtained and used to visualize the difference among the assembly conditions. Specimens of three groups including one original design, adding welds along the rims of the shadow mask in the direction of the horizontal axis and changing the thickness of the plate spring were investigated. From the AF-ESPI results, except the mode 3, the natural frequencies are increased by adding welding points along the rims in the direction of the horizontal axis. For the case of increasing the thickness of the plate spring, the natural frequencies of all modes are increased. Generally speaking, adding welds improve the vibration behavior for the third, fourth and fifth modes. The first and second modes, however, are predominated by the shadow mask. In addition, vibration characteristics of the sixth mode is not improved by changing the assembly conditions. KEYWORDS: assembly conditions, AF-ESPI, shadow mask, natural frequency, modal testing

Here, we propose a watermarking scheme that based on pixel position shifting (PPS). The proposed scheme will shift the watermark locations in the frequency domain such that the watermark locations are difficult to obtain by just using the watermarked image. To enhance the reliability of the retrieval of the watermark data, a (8,4) distance-4 Hamming code is used. The new proposed algorithm was thoroughly tested and substantial results will be given to prove the robustness of our method. In addition, we compare the results with our previous published method.

A wide variety of video services can benefit from application of a video pixel multiplier (VPM) that locally adds extra pixels for a higher resolution display. These services include Standard Definition Television (SDTV) displayed on a High Definition Television (HDTV) display, and Third Generation (3G) wireless mobile video transmission displayed on a higher-resolution display that could be used for fixed and mobile wireless.

In this work, the design and experimental characterization of a Wireless Infrared Direct-Sequence, Spread Spectrum (WIR-DSSS) system is presented. This prototype support low and medium data rates (up to 64 Kbps) enough for most consumer appliances, but can be easily increased to rates of about 1-2 Mbps if required. This system is designed to be used in the control and interconnection of heterogeneous appliances in the in-house environment, such as microwave ovens, washing machines, refrigerators, audio equipment, etc. The application of this technology for these kinds of channels allows the possibility of interchanging events without the need for a Line-of-Sight path between emitter and receiver. This eliminates the effect of ISI induced by multipath propagation and also permits the sharing of the channel avoiding the use of complex protocols (such as CSMA) using Code-Division Multiple-Access (CDMA) strategies.

But set makers, retailers plead for more programming from broadcasters Consumer electronics manufacturers and retailers are happy with early sales of DTV products, but need more HDTV content from broadcasters [...]

In this paper, we present a cryptanalysis of a remote user authentication scheme proposed by Hwang and Li. We show that Hwang-Li's scheme is breakable. A legitimate user can impersonate other legal users and pass the system authentication. Keywords--Cryptography; cryptanalysis; password authentication; remote login.